Chahoua Geckos and Underbites

Scooby and the "Fat Lip"

 

Scooby's parents were both unrelated Grand Terre animals from two different breeders and each was 5 1/2 years old at the time that he hatched. In the 3 prior years they have were paired, the female consistently laid 3 clutches and produced beautiful, healthy babies. In this particular year, she decided to drop a “surprise” 4th clutch and calcium-crashed directly after laying. The other egg turned out perfectly fine but Scooby came out with an underbite and was the first imperfect baby the pair ever produced.

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I always considered this situation when hearing of or looking at animals with underbites, and I started to notice a pattern: a lack of calcium in the mother while laying was frequently a part of the circumstance. I am not saying that this is necessarily breeder error, as we don’t have much control over how many clutches a female decides to lay in a year, especially if she decides to lay an extra at the end of the season when her calcium reserves might be depleted. It is common knowledge that these geckos are calcium-sensitive so it's logical to think that at the end of a season, the female may have been low on calcium, squeezed out one last clutch, and those babies suffered as a result of her deficiency.

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Less Calcium, More Underbites

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I have a longtime friend who lives near a local laboratory that has kept and bred New Caledonian species, including some Pine Island and Grand Terre chahoua pairs, for many years. The scientist who manages these animals only feeds baby food with a bit of calcium and unsupplemented crickets. Season after season, every offspring from every pair is born with an underbite.

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I think the results from that lab are quite interesting: with 6-7 pairs of unrelated animals from different locales producing 100% of babies with underbites, the logical question becomes what they have in common. The first and most obvious is husbandry and diet; the second could be incubation which I know nothing about. Baby food with just a bit of added calcium, and insects that are not dusted in a calcium supplement, are not enough to properly sustain chahoua. Much like in Scooby's case, lower or insufficient calcium is a common link. 

I want to be clear that I think there are different types of calcium deficiency:

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Situation 1: The laying female has low calcium reserves when laying eggs, the low calcium is somehow passed onto the eggs and embryo(s) and results in an underbite. This calcium deficiency can be from bad diet or being bred too early. This is what I presume happened to Scooby.

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Situation 2: A diet low in calcium is offered to a young, developing, healthy chahoua and impacts the animal's jaw structure while growing, resulting in an underbite.

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"Mostly Grand Terre chahoua have underbites - not Pine Island animals"

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In comparison to Pine Island chahoua, Grand Terre animals have the reputation of being more prone to underbites and many people assert that this is due to a lack of genetic diversity and inbreeding. I am not so sure that there couldn’t be another explanation…

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According to my research, Grand Terre animals were imported to the U.S. first and the Pine Island chahoua came about a decade later. Obviously, remarkable research and insight has been gained on the front of reptile nutrition in the last 20 years, and really, just in the last 10 years. For a very long time, baby food was the standard when feeding frugivorous geckos. After some trial and error, people realized that they needed to supplement the baby food with calcium, and then a while later, prepared diets such as Repashy Crested Gecko Diet or Pangea Gecko Diet were born. Now we are generations later and still making progress!

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It's quite likely that when the Grand Terre chahoua arrived in the mid- to late- 1980s, they were fed primarily baby food and/or insects because those were the best methods available at the time. Since this is not a complete or sufficient diet (and if my above assumptions are true), and considering the calcium-sensitive nature of chahoua, these geckos likely started producing a high number of offspring with underbites. As the numbers increased and feeding practices stayed the same, more and more chahoua with underbites were born. Today, I believe we are seeing fewer animals with underbites because we know more about how to correctly feed, supplement, and breed them which means this deformity is showing up less frequently.

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By the time the Pine Island animals arrived in captive collections, a decent number of GT chahoua had been produced in captivity with underbites, so that is what people came to expect of the Grand Terre locales. I have certainly seen a few PI animals with underbites, but GT chahoua suffer from the stigma moreso.

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Also consider: The New Caledonian geckos as a group have proven to be extremely resistant to the effects or mutations often associated with inbreeding, even over prolonged periods of time and multiple generations.

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In summary, it is most likely that Grand Terre chahoua get a bad reputation for underbites and “being too inbred” when it is actually human error and misunderstanding of their nutritional needs that caused this problem in the first place.

Scooby's Story - Continued!

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In late 2010, I decided to pair Scooby to a Grand Terre female that I owned because I was curious about whether or not the underbite was a truly genetic trait, as some have suggested. It was always my intention to keep any offspring in my possession considering the sensitivity of breeding an "imperfect" animal.

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The pair bonded, the female became gravid and later laid two eggs. One was infertile and the other was fertile and perfect, so I incubated it for 130-something days and out came Scooby's daughter, who is now named Wilma.

 

Wilma hatched out with a perfectly aligned jaw and reached adulthood with a perfectly shaped jaw and mouth: